Rolling-mill stand for reversing rolling

ABSTRACT

A rolling mill stand having at least three rolls for reversing rolling of rods or bars whose rolls are disposed vertically. From pass to pass either the rolling mill stand or the oppositely disposed tilting or lifting tables are vertically adjusted.

United States Patent Inventor Karl Jose! Neumann lngbert-Saar. Germany Appl. No. 750,955

Filed Aug. 7, 1968 Patented Aug. 10, 1971 Assignee Mueller 8: Neumann G.m.b.l'1.

lngbert-Saar, Germany ROLLING-MILL STAND FOR REVERSING ROLLING 2 Claims, 10 Drawing Figs.

[15. Cl. 72/223 lnt.C1. B2lb39/14 Field of Search 72/232,

[56] References Cited v UNITED STATES PATENTS 419,592 1/1890 Meysenburg et alm. 1 72/223 2,330,523 9/1943 Shaw 72/223 X 382,035 5/1888 Fawell et a1.... 72/233 1,556,031 10/1925 Rhodes 72/221 X Primary Examiner-Milton S. Mehr Anomey.lohn.l. Dennemeyer ABSTRACT: A rolling mill stand having at least three rolls for reversing rolling of rods or bars whose rolls are disposed vertically. From pass to pass either the rolling mill stand or the oppositely disposed tilting or lifting tables are vertically adjusted.

ROLLING-MILL STAND FOR REVERSING ROLLING This invention relates to rolling mill stands for reversing rolling and is more particularly concerned with a rolling mill stand having at least three rolls for reversing rolling of rods, or bars wherein each of the rolls is constantly driven in the reverse direction of rotation relatively to the adjacent roll or rolls and forms with each adjacent roll a rolling gap, the rods or bars to be rolled being movable into the nip of a respective rolling gap by-guide means disposed on both sides of the rolling mill stand.

This type of rolling mill stand is constituted most frequently by so-called three-high rolling mill stands which are provided with tilting or lifting tables on both sides of the stand. The tilting or lifting tables provided with roller tracks, transverse feeder devices and occasionally, with tilt devices, must guide the rods issuing from one reducing groove to the respective next reducing groove. Since the next following reducing groove is always located between the two horizontal rolls which-considered from the issued rolled rod-constitute a receiving-rolling gap, each issued rolled rod must always be displaced in height by one roll diameter for the next following reduction pass. This requirement determines the design of the drives for the heavy tilt and lifting tables which present a considerable cost in the production of three-high rolling stands because of the large masses to be accelerated.

It is also known to produce three-high rolling stands, or rolling stands with more than three horizontal rolls, which are adjustable in height in order to save tilt or lifting tables (French Pat. No. 1,362,50l). These can be constructed as simple reversible rolling tracks into which transverse feeder devices and tilt devices can be built with less expense than into tilt or lifting tables. But even in this new construction of rolling mill stands of the above-mentioned type for reversing rolling of rods having at least three rolls, the displacement stroke of the heavy stand for adjusting the respective receiving-rolling gap to a rolled rod depends always upon the diameter of the rolls.

Accordingly it is an object of the invention to reduce or to I avoid completely the mechanical expense for changing the positional height either of tilt or lifting tables or of rolling stands with three or more rolls. This object is attained according to the invention in that the rolls of e.g. a three-high rolling mill stand are disposed vertically. Thereby the change in height from one reduction groove to the next is reduced to the spacing between adjacent reducing grooves, hereinafter called groove distance, which is only a fraction of the roll diameter. Since the time for putting in position" a tilt or lifting table, or a stand which can be raised and lowered, in order to maintain the number of passes per unit time, remains constant, smaller inertia forces must be overcome in the case of a rolling mill stand with at least three rolls constructed in accordance with the invention, due to the reduced vertical adjustment path, so that a saving of cost is obtained for the lifting mechanism.

Admittedly, with the vertical position of the rolls of threehigh rolling mill stands the horizontal displacement path for the material to be rolled is increased in respect of the prior art, because now the respective next reducing groove is disposed at a location which is displaced laterally by the diameter of the roll; however, in this case only the rolled rod must be moved.

The vertical disposition of at least three rolls in a rolling mill stand for reversing rolling of rods is utilized further according to the invention in order that inlet and outlet roller tracks or tables, as well as rolls may be made stationary. A rolling'mill stand developed further in this respect is characterized by a number of more than three rolls operating with a fixed rolling gap, the number exceeding by one the desired number of passes, each intermediately disposed roll forming with the respective two adjacent rolls two successive reduction grooves at different levels of height, the positional height of the grooves decreasing successively in accordance with the required groove setting. The guide means for positioning the issuing rods in front of the next following reducing groove disposed one step lower can then be constructed as simple known tilt walls. If the rolls which are each provided with two reducing grooves are not offset relative to each other in a steplike manner but are disposed at the same level, the rods must be raised again after each second pass by one groove distance, this effect obviously also being attainable within the scope of the invention by lowering the stand. Compared with a three-high stand of new construction, such a rolling mill stand with more than three rolls has the advantage that the stroke displacement of the tilt or lifting tables, or the rolling mill stand, alternates only between two positional levels. The strokes could be limited by stops, so that it is unnecessary to guide the rods into the grooves by remote control.

Furthermore it was found that with a three-high stand also more than two passes can be effected in a single horizontal plane so that in the working roller tracks only transverse displacement means and under certain circumstances tilting devices must be provided. This rolling method is possible according to the invention in that the adjustable rolls form similar pseudo-oval reducing grooves, i.e. opened-out oval grooves, lying in a horizontal plane. In such a rolling mill stand are rolled always pseudo-ovals in which case the rolled rods must be turned from pass to pass. Adverse free broadening is reduced by the oval reduction pass.

In order that the rolled rods have a square cross section when they leave the stand, at least one finishing roll'pair is disposed on the outlet side ofa rolling gap, and the rod issuing from the last reduction pass is pushed therethrough. Only after the rod has left the respective roll pair of the three-high stand the last end of the rolled rod is driven through the finishing roll pair by means of a unidirectional coupling ofthe finishing roll pair.

Some embodiments ofa vertical multiroll rolling mill stand according to the invention are described below with reference to the accompanying drawings, in which:

. FIG. 1 illustrates a vertical three-high stand with stationary working roller tracks and a stand which can be lifted and lowered,

FIGS. 2 and 3 illustrate the disposition of the rolls and the sequence of reduction grooves of a vertical six-high rolling mill stand, in side view and plan view, respectively.

FIG. 4 illustrates a vertical six-high rolling mill stand in which the level of height of the reduction grooves decreases from pass to pass,

FIGS. 5 to 9 illustrate five adjustments of a vertical threehigh stand with similar pseudo-oval reducing grooves, and

HG. 10 is a diagrammatic illustration of the view from above on the rolls of a rolling mill stand according to FIGS. 5 to 9 followed by a finishing roll pair.

All embodiments have in common the vertical disposition of the rolls which is new for three or more rolls, each of the rolls being constantly driven in reverse direction of rotation relatively to each adjacent roll and forming a rolling gap therebetween. The rolling mill stand according to FIG. 1 is a vertical three-high stand having rolls 10, ll, 12 which are driven from'above. An electric motor 13 drives by way of a bevel gear drive 14, 15, a vertical shaft 16, a spur wheel drive 17 and one of three pinions 18. In the three pinions are guided telescopic spindles 19 which are connected to the three rolls, 10, 11, 12 by way ofjointed spindles 20.

The stand is guided in a vertical guide means not illustrated and is adapted to be raised and lowered by means of two threaded spindles 21. The spindles 21 run in stationary nuts which are mounted in housings 22. The nuts are driven also by the electric motor 13 by means of a worm shaft 23 and two worms 24, since the driving power of the motor is not required for rolling during lifting and lowering of the rolling stand.

The drive is taken off the bevel wheel 14 of the motor and extends through a reversing coupling 25 and a conical gearwheel stage 26 to the worm shaft 23. The rolling unit stand can be raised and lowered by means of the reversing coupling 25 in such manner that its reducing grooves are adjusted to the level of the working roller tracks are not illustrated, but the levels ofwhich are indicated by the line 27.

In the illustration according to FIG. 1 the vertical three-high stand is in the highest position. This is appropriately the level of the first reduction pass in order that between the passes only lowering movements occur. The pass sequence is consequently I, II, III, IV, V, from which may be seen that between the passes lowering movements only to the extent of a pass distance are necessary. For the pass V the three-high stand is in the lowermost position, and the reversing coupling 25 may be provided with a gear ratio for lifting the stand which permits the stand to return quickly to the original raised position.

In place of the vertically movable disposition of the threehigh stand obviously the working roller tracks may also be constructed as tilt or lifting tables. In this case also the advantage of smaller displacement strokes from pass to pass results when the rolls of the three-high rolling mill stand are disposed vertically.

FIGS. 2 and 3 as well as FIG. 4 illustrate rolling mill stands which have more than three rolls, namely a number of rolls which exceeds by one the desired number of reduction passes. As may be seen from FIG. 3 which is a diagrammatic top view of the arrangement according to FIG. 2 as well as also according to FIG. 4, six rolls are provided for five reduction passes (six-high rolling mill stand). Each outer roll 30, 3I, or 40, 41 (FIG. 4) has only one reducing groove, whereas each ofthe in terinediate rolls has two reducing grooves and forms always with the two adjacent rolls two successive reduction grooves at different positional heights. The pass sequence also denoted in FIG. 2 by I to V indicates clearly that with this disposition of the rolls at the same level the material to be rolled must change its height position relatively from pass to pass. The stand must be adapted to be raised and lowered corresponding to FIG. I, or alternately tilt or lifting tables must be used. The vertical movements however can be limited in an advantageous manner by stops, since the pass sequence is can ried out only in two horizontal planes.

After the last or fifth pass the rolled rod is fed-as may be seen from FIG. 3to a finishing roll pair 32. The rod is initially pushed through the finishing roll pair which is disposed a short distance beyond the stand; thereafter the roll pair 32 is driven by a motor 34 and a unidirectional coupling 33 when the rod in the last reduction pass V has left the rolling gap.

In the vertical six-high rolling mill stand according to FIG. 4 the positional height of the reducing grooves is reduced from pass to pass in accordance with the necessary groove distance, so that a steplike disposition of the rolls results. In this rolling mill stand the working roller tracks which are also disposed in steps can be stationary, and due to the decreasing positional height of the reducing grooves they may be inclined and provided with means for retaining rods which slide away, in front of the respective reducing groove. In this case the rolled material must be turned 90 between passes. It is also envisaged that known tilting walls are disposed between the individual grooves which effect simultaneously the lateral and downward conveyance.

The rolls in the six-high rolling mill stands according to FIGS. 2 to 4 operate with a fixed rolling gap; therefore they must be adjustable only for compensating wear of the reducing groove.

In accordance with the invention, a vertical three-high stand according to FIGS. 5 to has single-groove, adjustable rolls 50, 51 and 52. The rolls form similar pseudo-oval reducing grooves disposed in a horizontal plane, i.e. opened-out oval reducing grooves. The pass sequence which may be seen from FIG. 10 is the sequence of a normal three-high stand, with an additional pass Va in a finishing roll pair 53 which has a closed box groove for producing a square cross section. The finishing roll pair 53 the rolls of which may be disposed horizontal or vertical, is driven similar to the roll pair 32 in FIG. 3 by an electric motor 34 over a unidirectional coupling 33. In principle it is immaterial whether, as is known, the center roll 51 is adjustable and the two outer rolls 50,52 are not adjustable, or whether the center roll is stationary. In contrast to a normal three-high rollin method, however, e.g. an adjustable center roll 15 not only isplaceable to and fro, but at the same time the reducing grooves formed alternately with the roll 50 or the roll 52 are set closer. A pass reduction of the rolled material is then obtained as illustrated in FIGS. 5 to 9 for five passes. In FIG. 5 a square section rod is passed through the rolls 50 and 51 and is deformed to a pseudo-oval section. For reduction in the rolling gap between the rolls 51 and 52 according to FIG. 6 the rolled material is turned and deformed again along the long axis to a pseudo-oval cross section of smaller diameter. After the third to fifth pass according to FIGS. 7 to 9 a pseudooval section 54 is finally obtained by continuous closer setting of the working rolls which is finally rolled to a square section in the finishing roll pair 53.

Such a single-groove three-high stand with vertical roll disposition which operates with opened-out oval reducing grooves must be associated only with stationary working roller tracks with tilting devices and devices for transverse displacement.

The fact that the respective lower surface of the rolled rods attains a slightly higher level in the course of the progressing reduction, can be taken into account by a resilient disposition of the rollers of the working roller tracks, and it may also be envisaged to mount the roller track rollers eccentrically and to lift them from pass to pass by actuation ofthe eccentrics.

With reference to the six-high rolling mill stand according to FIG. 4 it must be stated further that when such a stand is used as initial stand for a continuous rolling mill a high inlet speed can be obtained which in turn is accompanied by reduced cooling. The production depends merely upon the rolling speed in the last roll pair. Compared with the threehigh constructions according to FIGS. I and 5 to 10, the sixhigh constructions according to FIGS. 2 to 4 have the com mon advantage that there is freedom in the choice of the rolled sections.

What I claim is:

1. In a rolling mill stand for reversing rolling of rod stock or the like comprising, in combination, a support stand arranged for vertical adjusting movement, means for moving said support stand vertically to a selected level, at least three rolls rotatably mounted on said stand in adjacent relationship for rotation on a vertical axis, means for rotating each of said vertically disposed rolls in the opposite direction of rotation rela tive to the adjacent roll, at least one pair of cooperating roll grooves in the peripheral surfaces of each pair of adjacent rolls to form a rolling gap for rolling ofsaid rod stock, said one pair of cooperating roll grooves in each of said pairs of adjacent rolls being disposed in vertically displaced relationship with the pair ofcooperating roll grooves in the adjacent pair of rolls for rolling of said rod stock in opposite directions alternately through said roll groove pairs in each of said pair." of adjacent rolls, said support stand being movable by said moving means to position each of said pair of cooperating roll grooves at said selected level for said reversing rolling of said rod stock.

2. A rolling mill stand in accordance with claim I including a plurality of pairs of cooperating roll grooves in the peripheral surfaces of each pair of adjacent rolls, said pairs of cooperating roll grooves in each pair of adjacent rolls being disposed in vertically displaced relationship with each other and with the pairs of cooperating roll grooves in the adjacent pair ofrolls. 

1. In a rolling mill stand for reversing rolling of rod stocK or the like comprising, in combination, a support stand arranged for vertical adjusting movement, means for moving said support stand vertically to a selected level, at least three rolls rotatably mounted on said stand in adjacent relationship for rotation on a vertical axis, means for rotating each of said vertically disposed rolls in the opposite direction of rotation relative to the adjacent roll, at least one pair of cooperating roll grooves in the peripheral surfaces of each pair of adjacent rolls to form a rolling gap for rolling of said rod stock, said one pair of cooperating roll grooves in each of said pairs of adjacent rolls being disposed in vertically displaced relationship with the pair of cooperating roll grooves in the adjacent pair of rolls for rolling of said rod stock in opposite directions alternately through said roll groove pairs in each of said pairs of adjacent rolls, said support stand being movable by said moving means to position each of said pair of cooperating roll grooves at said selected level for said reversing rolling of said rod stock.
 2. A rolling mill stand in accordance with claim 1 including a plurality of pairs of cooperating roll grooves in the peripheral surfaces of each pair of adjacent rolls, said pairs of cooperating roll grooves in each pair of adjacent rolls being disposed in vertically displaced relationship with each other and with the pairs of cooperating roll grooves in the adjacent pair of rolls. 